1. Field of the Invention
The present invention relates generally to a semiconductor process, and more specifically to a semiconductor process, wherein an ozone saturated deionized water process is carried out to form an oxide layer and an annealing process is performed after a dielectric layer is formed.
2. Description of the Prior Art
Poly-silicon is conventionally used as a gate electrode in semiconductor devices such as metal-oxide-semiconductors (MOS). With the trend towards scaling down the size of semiconductor devices, conventional poly-silicon gates face such problems as lower performances due to boron penetration and unavoidable depletion effect, which enlarges the equivalent thickness of the gate dielectric layer, reduces the gate capacitance, and worsens the driving force of the devices. Therefore, work function metals that are suitable for use as the high-K gate dielectric layer are used to replace the conventional poly-silicon gate to be the control electrode.
Due to the material difference in a gate dielectric layer having a high dielectric constant and a substrate, a buffer layer will be deposited between both of them before the dielectric layer having a high dielectric constant is deposited on the substrate. The buffer layer may be an oxide layer, and may be formed by an in situ steam generation (ISSG) process. AS the size of semiconductor components are miniaturized, the effective oxide thickness (EOT) and the gate leakage (Jg) are difficult to minimize because of process limitations.
A semiconductor process that can reduce the effective oxide thickness (EOT) and the gate leakage (Jg), are extremely needed to reach the demand of semiconductor scaled down components.